The invention relates to entrained flow gasification of differing ash-containing solid and liquid fuels with an oxidizing agent containing free oxygen at pressures up to 10 MPa and gasification temperatures up to 1900° C. Solid fuels in this case are coals of differing degrees of coalification milled to powder, petroleum cokes and other millable solids from the waste and recycling economy. Liquid fuels are taken to mean oils, oil-solids suspensions, and also coal-water suspensions, termed slurries.
In the technology of gas generation, autothermal entrained flow gasification has been known for many years. The ratio of fuel to oxygen-containing gasification agent is selected in this case such that temperatures are achieved which are above the melting point of pulverized fuel ash. Then, the ash is melted to give liquid slag, which leaves the gasification chamber together with the gasification gas and is then cooled.
An extensive description of the prior art with various designs of the quench system may be found in J. Carl inter alia, NOELL-KONVERSATIONSVERFAHREN, EF-VERLG für Energie-und Umwelt-technik GmbH 1996 [Noell Conversion process, ef-verlag für Energie-und Umwelt-technik GambH 1996]. The direct cooling of hot crude gasification gas and liquid slag described therein by injecting water in excess cools the crude gas to saturation temperature which is dependent on the gasification pressure. If the gasification pressure is, for example, 40 bar, the crude gas is cooled to approximately 210° C. and is steam-saturated. The slag that is cooled in the same manner collects in the water bath in the lower part of the quench chamber and is discharged, the steam-saturated crude gas leaves the quench chamber at the side and is fed to further purification stages, for example a Venturi scrubber for further dust separation. Quench water is provided in this case via a process water circuit to which process condensates and fresh water are supplied as makeup after the solids separation. The solutions of the prior art have the disadvantage that a considerable part of the solids that are entrained by the crude gas and consist of small slag particles and soot are not scrubbed out in this simple system and require the subsequent purification stages. The fine solids are in part transported through the entire process chain and lead to operating faults.
The object of the invention is to specify a device for quenching in a gasification appliance, which ensures safe cooling of the crude gasification gas and at the same time separates off a high proportion of the entrained dust and binds it in surplus water.
The crude gas generated with the device according to the invention exhibits a considerable reduction in the loading with particles.
The invention will be described in more detail hereinafter in 3 examples on the basis of 3 figures to an extent necessary for understanding.